NOのアンモニアとヒドロキシラミンに対する電気還元におけるコバルトの構造的感受性に関する計算的洞察
Pu Guo1, Dong Luan1, Huan Li1,2
1State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, P.R. China.
Journal of the American Chemical Society
|May 9, 2024
まとめ
六角密集コバルトは,電解酸化窒素還元 (eNORR) でアンモニアの生成に優れているが,単原子コバルト触媒はヒドロキシラミンに優れている. 触媒の構造は反応の選択性を決定的に影響する.
科学分野:
- 電気化学
- カタリシス
- 材料科学
背景:
- 窒素化合物の合成には,電解酸化窒素還元 (eNORR) が不可欠である.
- 六角密集型コバルト (hcp) はアンモニアの選択性を示しているが,面中心立方体コバルト (fcc) とコバルト単原子触媒 (Co-SAC) は異なる選択性を示している.
研究 の 目的:
- eNORRにおけるhcp-Co,fcc-Co,およびCo-SACの構造的感受性を調査する.
- アンモニアとヒドロキシラミンに対する選択性を支配するメカニズムを解明する.
主な方法:
- 定数ポテンシャルシミュレーション法
- マイクロキネティックモデル
主要な成果:
- hcp-Coは,容易な電子/陽子の移転とNO*抑制により,アンモニアに対する優れた活性を示している.
- Co- SACは,陽性電荷の活性センターと適度なNO吸収に起因する例外的なヒドロキシラミン選択性を表しています.
- NOH*の形成は,hcp-Coとfcc-Coで好まれるが,HNO*は,NOの吸収強度と向きに関連して,Co-SACで好まれる.
結論:
- NO*プロトネーションの第一段階は,eNORRにおける選択性制御に極めて重要です.
- 触媒の局所および電子構造は,ENORRにおける活動と選択性を大きく制御する.
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